generate_request does nothing more than build a urlencoded xml string that looks like this:%3Creq%3E%3Cemail%3E%3Crecipient%3E127c08d531eb161d2c02d4404706b623%3C%2Frecipient%3E%3Clist%3E4133%3C%2Flist%3E%3C%2Femail%3E%3C%2Freq%3E